Single-qubit gates
Beginner · 4 lessons · 18 activities
A gate is a reversible rotation of a state, not a truth table. Meet X and H, learn to read a circuit left to right as a sequence of time slices, and practise reaching a state you were handed rather than pushing symbols around.
Lessons
Gates move the state
A gate is a rotation, not a truth table. Meet X and H by driving a qubit with one gate at a time, then find the case where X stops behaving like NOT.
5 activities · 13 min
Reading a circuit
A circuit is one qubit's history read left to right. Learn what a wire means, why the order of two gates changes the answer, and how to undo a circuit you were handed.
5 activities · 13 min
Rotations by any angle
X and H are two rotations out of infinitely many. Turn a qubit by an angle you choose, meet the half-angle that trips everyone up, and tune a circuit to the odds you were asked for.
4 activities · 11 min
Reach a state you were handed
Stop pushing symbols and start solving: read a target off the circle, find a circuit that reaches it, and recognise when two different circuits are the same gate.
4 activities · 12 min